Data from several cancer screening studies are being analyzed to gain a better understanding of the impact and consequences of such screening in various population settings, and to develop new techniques for data analysis. Results from the Health Insurance Plan of New York breast cancer screening trial continue to indicate a long-term reduction in breast cancer mortality. In collaboration with the Biostatistics Branch, DCE, patterns of case survival and cause of death are being related to population mortality measures to further assess the nature of the screening benefit. A group collaborating through the International Agency for Research on Cancer is analyzing the cervical cancer screening programs in Scandinavia and Aberdeen, Scotland to estimate false negative rates and natural history characteristics, and relate these to the varying screening parameters in the participating countries. Two occupational high risk groups are under scrutiny. In collaboration with DCE, the bladder cancer screening program at the DuPont Company is being analyzed to relate disease characteristics and outcome to cytology and blood tests, smoking history and chemical exposure. With DCE and the National Institute of Occupational Safety and Health, updated follow-up data are being collected in a study of sputum cytology screening for lung cancer among uranium miners. The relationships among cytology classification, radiation exposure, smoking history, lung cancer, and mortality data will be analyzed. Participation in an International Union Against Cancer screening evaluation project resulted in a monograph on methodologic issues in screening, plus evaluation of lung, bladder and oral cancer screening.